This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Dectin-1 is a pattern recognition receptor that is known to have an important role in host neutrophil response to fungal pathogens via interactions with fungal carbohydrates. However, the carbohydrate-protein binding surface is currently unknown. To this end, dectin-1 has been expressed and isolated, along with a high-affinity glucan phosphate. In order to determine the carbohydrate binding surface, we are using hydroxyl radical footprinting by flash photolysis of peroxide to differentially label the protein in the presence and absence of a high-affinity glucan phosphate. After modification, we will determine the extent of modification at each oxidation site, and use differences in apparent rates of oxidation to determine differences in solvent accessibility at the oxidation site.